The present invention relates to an apparatus for controlling a windshield wiper of a vehicle and, more particularly, to a windshield wiper control apparatus for automatically controlling the speed of the wiper operation and the intervals of intermittent cyclical wiper operation to give a driver a clear view to thereby assure a safety vehicle operation and an economical wiper operation.
The inventors of the present application have been engaged in the development of windshield wiper control apparatus for use on a vehicle which includes a light-emitting unit adapted to be mounted on the vehicle outside the occupant compartment, a light-receiving unit adapted to be mounted on the vehicle in the compartment for receiving the rays of the light emitted by the light-emitting unit and passed through a predetermined area of the windshield and control means responsive to the rays received by the light-receiving unit to judge the quantity of raindrops on the windshield for thereby automatically controlling the wiper operation.
The apparatus further includes an infrared transmission filter for reflecting visible light and a slit or masking plate having light-transmission slits and light-shielding zones arranged on the plate in a striped pattern. The filter and the slit plate are disposed both at the front portion of the light-receiving unit. The existence of these two elements, i.e., the filter and the slit plate, not only leads to the increase in the steps of assembling component parts of the unit but also complicates the structure thereof. In addition, in the case where the filter is placed in front of the slit plate so as to facilitate easy removal of dust, visible light is reflected by the outer surface of the filter plate, which will possibly spoil the front view of the windshield of the associated vehicle.